Question: Do I weigh less on the equator than at the North Pole?

Ryan Durnall answered on 13 Mar 2024: last edited 14 Mar 2024 1:01 am

I recognise this question from our chat earlier today! Sorry we ran out of time before you could get an answer. It’s a brilliant question, by the way. You’re absolutely correct, people and things do weigh less at the equator than at the Poles, for two reasons;

The Earth isn’t a perfect sphere. Earth is spinning and this creates a bulge around the centre. This means the equator is further away from the core of the Earth than the Poles. By being further away from most of the Earth’s mass, gravity is pulling less on you than if you were closer to it (At the poles).

The second reason is that the bulge around the centre is caused by centrifugal force as the Earth spins. This force opposes gravity and as always, less gravity means your weight is less.

Another really important thing to remember is weight is not the same as mass. The mass of an object is simply how much matter/stuff it is made up of. The weight of an object changes depending on how much gravity is acting on it. To get the weight of an object, we have to multiply mass by gravity. So next time someone asks you how much you weigh, tell them it depends on gravity. What they’re really meaning to ask you is how much your mass is. Both are quite impolite, but at least one of them is scientifically correct!